Valve for evaporative loss control

ABSTRACT

Diaphragm valve spring biased into a closed position and responsive to fuel tank vapor pressure to effect opening of valve, and to fuel tank vacuum as the valve is closed, to vent the tank to atmosphere.

United States Patent 1191 Soberski June 26, 1973 VALVE FOR EVAPORATIVELOSS [56] References Cited CONTROL UNITED STATES PATENTS [75] Inventor:George A. Soberski, Des Plaines 2,947,313 8/1960 Taylor 137/1023,460,558 8 1969 J h 137 102 [73] Assgnee f h'c'icleveland 3,084,707811963 1371102 01110 2,917,070 12/1959 Langdon 137/496 [22] Filed: Oct.12, 1970 Primary Examiner-Martin P. Schwadron [21] Appl' 79346 AssistantExaminer-A. M. Zupcic Related US. Application Data Attorney-John R.Dwelle [62] Division of Ser. No. 783,821, Dec. 16, 1968, Pat. No.

3,628,517. [57] ABSTRACT Diaphragm valve spring biased into a closedposition [52] US. Cl 137/102, 137/512.l5, 137/525 and responsive to fueltank vapor pressure to effect E2 gz' d l' opening of valve, and to fueltank vacuum as the valve is closed, to vent the tank to atmosphere.

3 Claims, 9 Drawing Figures VALVE FOR EVAPORATIVE LOSS CONTROL Thisapplication is a division of my application, Ser. No. 783,821, filedDec. 16, 1968, now US. Pat. No. 3,628,517 and entitled Valve ForEvaporative Loss Control.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to evaporative loss control apparatus, and in particular tovalve apparatus for controlling evaporative loss in the fuel system ofan automotive engine.

2. Description of the Prior Art Evaporative loss control devices havefound particular use in automotive fuel systems to purge fuel vaporsfrom the fuel reservoirs during engine operation; to store vapors afterengine operation when the fuel system is in an immediate overheatcondition; and to return vapors to fuel reservoirs for condensationafter cool down of the system, in cooperation with the carburetor and avent switchv of the automotive engine.

Heretofore, such apparatus employed at least two separate, butcooperable valves to channel the air and fuel vapors between theplurality of fuel reservoirs and the carburetor. In addition to theobvious disadvantage of requiring additional parts, the provision of aplurality of valves to provide the purging and venting operations, has anumber of other disadvantages. One of these is the added designrequirements for each valve and the cooperable parts thereof.Furthermore, the additional number of parts requires longer per unitassembly time. It is therefore desirable for evaporative loss controlapparatus to employ a single valve for providingthe venting and purgingoperations.

SUMMARY AND OBJECTS OF INVENTION At the top of the housing are first andsecond passageways in communication with the chamber. The firstpassageway is adapted for connection to a carburetor line and through avent switch to the upper throat portion of a carburetor. The secondpassageway is adapted for connection to a purge line which is incommunication with a vacuum port adjacent the butterfly valve in a lowerthroat portion of the carburetor as a vacuum input to the device.

Evaporative loss control valve for the fuel control tank of an internalcombustion engine in which the valve is in the form of a diaphragmbiased into a closed condition, and opened by fueltank vapor pressure.The valve is seated on an outlet port connected with a carburetor purgeline and has a fuel tank inlet connection on the underside of thediaphragm which effects opening of the outlet port upon positive fueltank vapor pressure conditions. The inlet connection to the fuel tankalso supplies vacuum to the underside of the diaphragm valve to flex thevalve when closed and open a passageway leading through the valve toconnect the fuel tank to atmosphere until the pressure in the tank isbalanced.

A principal object of the present invention, therefore, is to provide asimplified form of single diaphragm valve particularly adapted forcontrolling the evaporative loss from a fuel tank and operable to effectdifferent operations by vapor pressure or vacuum in the fuel tank.

Another object of the invention is to improve upon the evaporativecontrol valves, for fuel tanks for internal combustion enginesheretofore known, by so arranging the valve that a single diaphragm cancontrol the purging of the tank under certain pressure conditions andthe venting of the tank to atmosphere under certain other pressureconditions.

Other objects, features and advantages of the invention will be readilyapparent from the following description of a preferred embodimentthereof, taken in conjunction with the accompanying drawings, althoughvariations and modifications may be effected without departing from thespirit and scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS The invention, its organization,construction and operation, according to one illustrative embodimentthereof, will be best understood from the following description taken inconjunction with the accompanying drawings, in which:

FIG. 1 is a top plan view of an evaporative loss control deviceaccording to the present invention;

FIG. 2 is an elevational view, in section, of the apparatus of FIG. 1taken along the line IIII;

FIGS. 3 and 4 are more detailed views of the valve I apparatus shown inFIG. 2;

FIG. 5 is a modification of the apparatus of FIGS. 2, 3 and 4; and

FIGS. 6-9 are schematic diagrams of an evaporative loss fuel vaporsystem according to the present invention shown in various operationalmodes of the associated automobile engine.

DESCRIPTION OF THE PREFERRED I EMBODIMENTS In FIGS. 15, an evaporativelosscontrol device is generally shown at 10 ascomprising a hollowcanistertype housing 11 defining a chamber 14 therein. Mounting flanges12 having slotted tabs 13 are provided for securing the device withinthe engine compartment of an automobile.

Chamber 14 is filled with an absorbent material, preferably activatedcharcoal or a shredded rubber compound for collecting fuel vapors. Atthe lower end of device 10 and against the absorbent material is ascreen or porous material 15 against which is located a pressure plate16 having a plurality of holes 17 therein. A spring retainer 19 having araised ridge portion 20 compresses spring 18 against the bottom of thepressure plate 16 and is secured to the hollow housing 11 by edgeportions 22 and 23 which form a groove for accepting an annular ridge 24at the lower end of the housing. A removable plastic cover 25 having alarge opening 28 in the center thereof holds a filter 29 against thespring retainer 19 and releasably engages the spring retainer 19 by theoverlapping portions 26 and 27 which overlappingly engage portions 22and 23 of the retainer. The air passage into the bottom of the device 10is therefore defined by opening 28, filter 29, hole 21, holes 17 andscreen 15.

At the top of the device 10, and adjacent the top surface of theabsorbent material is a screen 30 which is spaced from the top of thechamber 14 by spacers 33 to define chamber 34 therebetween. The top ofthe housing further defines a plurality of passageways including a firstpassageway 37 which is defined by wall 36 of top portion 35. Passageway37 is adapted for connection to a fuel tank line for venting and purgingvapors with respect to the fuel tank. Passageway 37 is in communicationwith a chamber 38 which is formed between the top portion 35 of housing11 and a rubber diaphragm 39 which is secured by its bead portion 51which is held in groove 50 by a spring housing 57. The spring housing 57is secured to the top portion 35 by means of portions 59 forming a snapfit with an annular groove 58 of the top portion 35.

Spring housing 57 holds spring 64 against a pressure plate 56 having anaperture 55a therein for receiving a snap button 55 of diaphragm 39. Thespring 64 therefore urges diaphragm 39 downwardly against rounded endportion 49 of cylinder 41 formed in the upper portion 35, the cylinder41 extending downwardly into a well 32 of screen 30 within the chamber14.

Under conditions of positive pressure, symbolized by arrows 65 and 66,from the fuel tank line through passageway 37 into chamber 38, diaphragm39 and pressure plate 56 operate against the action of the spring toopen the seal between the flat portion 53 of the diaphragm and therounded end portions 49 of cylinder 41 to permit fluid communicationbetween the fuel tank and chamber 14 via a path including passageway 37,chamber 38, passageway 40 of cylinder 41, slots 42 at the lower end ofcylinder 41 and screen well 32.

Under conditions of negative pressure within the fuel line andaccordingly within passageway 37 and chamber 38, the spring 64 closesthe above-mentioned path at end 49 of cylinder 41. Further, ambient airpressure transmitted through slot 63 of portion 35, filter 62, and holes61 in spring housing 57 into chamber 60 acts on a first flexible portion52 of diaphragm 39 to flex portion 53 thereof sufficiently to provide acontinuation of the just-traced path through holes 54-of diaphragm 39into chamber 38 and-on through passageway 37 to the fuel tank line.

FIG. illustrates a variation of the valve shown in detail in FIGS. 3 and4 wherein a diaphragm 39a includes an annular upstanding ridge as a sealagainst the pressure plate 56. The operation of diaphragm 39a issubstantially the same as that of the diaphragm 39.

A top portion 35 has two additional passageways formed therein. One ofthese passageways 43 is adapted for connection to a carburetor line andcommunicates the carburetor line with chamber 14 by way of slots 42 (forgreater vapor dispersion) of a downwardly extending portion ofpassageway 43. This passageway is for communication between thecarburetor and the chamber 14 by way of a purge line 79, as illustratedin FIGS. 6-9, whereby a vacuum may be supplied to the chamber 14.

Another passageway 45, has a depending cylindrical portion 47 defining afurther passageway 46 having a slotted end (slots 48) extending intoscreen well 31 of screen 30 within chamber 14, the passageway 45 beingadapted for connection to a line 73 for providing communication betweenthe chamber 14 and a vent switch 74 and a fuel bowl 75 of a carburetor,as also illustrated in FIGS. 6-9.

OPERATION The various operational modes of the evaporative loss controlvapor system according to the present invention are shown in FIGS. 6-9wherein a limited number of reference characters are employed for sakeof clarity.

FIG. 6 describes a condition wherein the automotive engine isinoperative and cold, the fuel system also being cold and no fuel vaporsbeing generated in the fuel tank 81 or in the carburetor hole 75.

Under such conditions, the butterfly valve 78 of car buretor 71 isclosed there being no vacuum supplied through purge line 79 topassageway 43 of device 10. The vent switch 74 is positioned to closeline 72 which extends to the upper throat area of the carburetor 71 andopen to line 73 to place the fuel bowl 74 in communication with chamber14 via passageway 45. In FIGS. 6-9 reference 76 indicates fuel level andreference 77 indicates a fuel line extending between the carburetor andthe fuel of the fuel bowl 75. There being no pressure difference betweenthe fuel tank 81 and ambient conditions, diaphragm 39a is closed.

FIG. 7 illustrates the conditions of fuel system when the automotiveengine is in operation, the engine being on and hot and the fuel systembeing sufficiently warm so that fuel vapors are generated in the fueltank 81 and the carburetor bowl 7 5.

Under these conditions, the diaphragm 39a is opened to the positivepressures developed in fuel tank 81, symbolized by arrows 90. Thebutterfly valve 78 is opened providing a vacuum through purge line 79 topassageway 43 of the loss control device 10. The vent switch 74 isopened to the carburetor, but closed to line 73 and passageway 45.Therefore,- vapors from tank 81 pass to the carburetor over a pathcomprising line 80, passageway 57, chamber 38, passageway 40,'chamberl4, passageway 43 and purge line 79. In chamber 14 air is drawn inthrough hole 21, (symbolically representing the holes and filters at thelower part of the canister), the air being mixed with the fuel vaporsand the material of chamber 14 being purged of fuel vapors by the vacuumsupplied by the carburetor.

FIG. 8 illustrates the condition of immediate overheat wherein theengine has just been turned off and is still hot and the system is hotwherein fuel vapors are still being generated to positive pressures inthe fuel tank 81 and the carburetor bowl 75.

In this situation, the butterfly valve 78 is closed and no vacuum issupplied to chamber 14. The vent switch is closed to the carburetor, butopened to lines 73 and passageway 43'into chamber 14 so that fuel vapors90 may traverse this path into chamber 14. Also fuel vapors 90 from fueltank 81 establish a positive pressure on the lower side of disphragm 39aurging the diaphragrn against the action of spring 64 so thatthese'vapors are also passed into the chamber 14. In such a case theactivated charcoal or shredded rubber compound absorb these fuel vaporsuntil the fuel system is cool enough to re-accept these vapors forcondensation.

FIG. 9 illustrates the venting of the system to the atmosphere underconditions of negative pressure wherein the engine is off and has cooleddown and the system fuel vapors are cooling sufficiently forcondensation.

In FIG. 9, a negative pressure is established in chamber 38 (see FIG. 4)so that diaphragm 39a is flexed to the extent that fluid communicationis established between the atmosphere and the fuel tank 81 over a pathcomprising holes 61, chamber 60, holes 54 of diaphragm 39a, passageway37 and fuel tank line 80. By this action, any vapors within chamber 38,passageway 37 and fuel tank line 80 are forced back into the fuel tank81 for condensation.

Inasmuch as the engine is off and the butterfly valve 78 is closed, novacuum is supplied to the chamber 14 via passageway 43; however, fluidcommunication is established between the atmosphere and fuel bowl 75since vent switch 74 is opened to the evaporative loss control device.Such communication comprises the path of hole 21, chamber 14, passageway43 and carburetor line 73, the negative pressures established in thefuel bowl drawing air through hole 21 to force vapors over thejust-traced path for condensation within the fuel bowl.

Although I have described my invention by reference to specificillustrations, many changes and modifications thereof will be evident tothose skilled in the art without departing from the spirit and scope ofmy invention as set forth in the appended claims.

What I claim as my invention is:

l. A vacuum and pressure operated valve apparatus comprising:

a housing defining a chamber therein having a first passage opened tothe atmosphere and a second passage cmmmunicating pressure or vacuum tosaid apparatus;

a diaphragm secured within said housing and dividing said first chamberinto second and third chambers,

said first passage communicating with said second chamber and saidsecond with said third chamber;

said diaphragm having continuous inner and outer area portions, saidinner portion having a thicker cross section than said outer portion todefine a diaphragm more flexible over said outer portion than said innerportion, said inner portion further having a plurality of openingsadjacent its outer extremity;

a plate affixed to one side of said diaphragm and of sufiicient area toextend over said openings in said inner portion to prevent communicationbetween said first and second passages when said second passage is atpressure at least equal to atmosphere;

spring means in said second chamber biasing said plate toward said thirdchamber; and

means forming a third passage in said third chamber communicating withsaid second passage when said second passage is at pressure at leastequal to atmosphere and sealed from said second passage by said innerportion when said second passage is at vacuum.

2. The valve apparatus of claim 1 wherein said inner portion of saiddiaphragm has a raised annular rib construction at its outer extremityin sealing engagement with said plate when said second passage is atpositive pressure, said openings in said inner portion being disposedinwardly of said rib.

3. The valve apparatus of claim 2 wherein said inner portion of saiddiaphragm has a raised projection extending from one side at its centerand said plate has a central opening which snugly receives saidprojection to maintain said plate in position.

passage communicating

1. A vacuum and pressure operated valve apparatus comprising: a housingdefining a chamber therein having a first passage opened to theatmosphere and a second passage cmmmunicating pressure or vacuum to saidapparatus; a diaphragm secured within said housing and dividing saidfirst chamber into second and third chambers, said first passagecommunicating with said second chamber and said second passagecommunicating with said third chamber; said diaphragm having continuousinner and outer area portions, said inner portion having a thicker crosssection than said outer portion to define a diaphragm more flexible oversaid outer portion than said inner portion, said inner portion furtherhaving a plurality of openings adjacent its outer extremity; a plateaffixed to one side of said diaphragm and of sufficient area to extendover said openings in said inner portion to prevent communicationbetween said first and second passages when said second passage is atpressure at least equal to atmosphere; spring means in said secondchamber biasing said plate toward said third chamber; and means forminga third passage in said third chamber communicating with said secondpassage wheN said second passage is at pressure at least equal toatmosphere and sealed from said second passage by said inner portionwhen said second passage is at vacuum.
 2. The valve apparatus of claim 1wherein said inner portion of said diaphragm has a raised annular ribconstruction at its outer extremity in sealing engagement with saidplate when said second passage is at positive pressure, said openings insaid inner portion being disposed inwardly of said rib.
 3. The valveapparatus of claim 2 wherein said inner portion of said diaphragm has araised projection extending from one side at its center and said platehas a central opening which snugly receives said projection to maintainsaid plate in position.